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    <script>
        function myInstanceof(A, B){
            var _A = A.__proto__,
                _B = B.prototype;

                while(_A != _B){
                    _A = _A.__proto__;
                    if (!_A){
                        return false;
                    }
                }
                return true;
        }
        console.log(myInstanceof([1, 2], Array));
        console.log(myInstanceof({}, Function));
        console.log(myInstanceof(Object, Function));
    </script>
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